From 28a89453b1e8de8d777ad96fa1eef27b5d1ce074 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 12 Feb 2008 18:07:27 -0800 Subject: [PATCH] [IPV6]: Fix IPsec datagram fragmentation This is a long-standing bug in the IPsec IPv6 code that breaks when we emit a IPsec tunnel-mode datagram packet. The problem is that the code the emits the packet assumes the IPv6 stack will fragment it later, but the IPv6 stack assumes that whoever is emitting the packet is going to pre-fragment the packet. In the long term we need to fix both sides, e.g., to get the datagram code to pre-fragment as well as to get the IPv6 stack to fragment locally generated tunnel-mode packet. For now this patch does the second part which should make it work for the IPsec host case. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 6 +++++- net/ipv6/xfrm6_output.c | 2 +- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 9ac6ca2521c..4e9a2fe2f12 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -621,7 +621,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *)) * or if the skb it not generated by a local socket. (This last * check should be redundant, but it's free.) */ - if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) { + if (skb->local_df) { skb->dev = skb->dst->dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS); @@ -1420,6 +1420,10 @@ int ip6_push_pending_frames(struct sock *sk) tmp_skb->sk = NULL; } + /* Allow local fragmentation. */ + if (np->pmtudisc >= IPV6_PMTUDISC_DO) + skb->local_df = 1; + ipv6_addr_copy(final_dst, &fl->fl6_dst); __skb_pull(skb, skb_network_header_len(skb)); if (opt && opt->opt_flen) diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c index b34c58c6565..79ccfb08073 100644 --- a/net/ipv6/xfrm6_output.c +++ b/net/ipv6/xfrm6_output.c @@ -36,7 +36,7 @@ static int xfrm6_tunnel_check_size(struct sk_buff *skb) if (mtu < IPV6_MIN_MTU) mtu = IPV6_MIN_MTU; - if (skb->len > mtu) { + if (!skb->local_df && skb->len > mtu) { skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev); ret = -EMSGSIZE; -- 2.20.1